In Oregon, where I grew up, agriculture thrives in part because of seasonal snow storage in the Cascade Mountains, which melts into the river system in late spring and summer and provides water during the portion of the year when there’s little rain in the valley. The Willamette Valley, which is on the western side of the Cascades, is also extremely fertile due to the sediment deposits left behind by glaciers that were present in the region thousands of years ago. The region I am studying for my PhD research is the Karakoram and Himalayan Mountains in Asia, which, like the Cascade Mountains, store water for future use. Hundreds of millions of people in India, China, Pakistan, and Nepal live downstream of the Karakoram and Himalayan Mountains and rely on water from the mountains for most aspects of life.
The Karakoram and Himalayan Mountains are extremely steep and contain many of the highest peaks in the world. The Karakoram and Himalaya Mountains have many more glaciers than the Cascades, which have been storing water for thousands of years. In addition to being a natural reservoir of water, the glacial sediment mixed into the glacier melt water helps fertilize the downstream agriculture.
Climate change is affecting both the seasonal snow storage and the longer-term storage by the glaciers. So far in my research, I’ve focused on modeling projections of future snowfall in the regions, and have found that annual snowfall in the region may decrease by 20 to 50%, depending on how much the climate changes. These changes in snowfall are caused by increases in temperature and changes to precipitation, which will also impact glacier mass in the region. My future work will be to model projected changes to the glaciers, then combine this with the snowfall projections and other important hydrological processes, to model climate change affects on river water availability.
Any significant changes to the water availability in this region will be potentially disruptive for the hundreds of millions of people living downstream. By understanding these changes before they happen, we can work to minimize the drivers behind the changes and mitigate the impacts of them. Through this understanding and preparation for the likely changes, hopefully all of us – the people living downstream of the Karakoram, Himalaya, and Cascade Mountains – can continue to have plentiful water resources and glean all the other benefits of having healthy glaciers.
- Thomas, Oregon State University, USA